Memory Retention and Sleep
Among the many other functions of sleep, memory formation and retention is perhaps the most important. The brain processes memories in two ways: through helping learn and focus and through helping with memory retention and recall. 1
The brain must go through a process that allows memories to be created and restored. First, acquisition or the actual learning or performing a new task must occur. Next, consolidation or making the memory stable in the brain occurs. Finally, recall or the ability to access a memory is the completion of the memory. Researchers feel that consolidation must happen while asleep. 1
Any college student will report at least one instance of pulling an all-nighter to study for an exam or finish a project, but how effective is this method? College students are among the most sleep deprived in the nation, presumably because newly established freedom, class and work load and social pressures. Sleep deprivation on its own will reduce mental functioning, and, therefore, pulling an all-nighter is counterproductive. Many studies have been done all concluding that, while immediate recall of information is possible, retention is ultimately nonexistent. Staying up all night and “cramming for an exam will not be nearly as effective for students as the same amount of effort followed by a good night’s sleep.
The same intense neuron firing during REM sleep that is thought to produce dreams is also responsible for aiding in memory retention. This explains why we may dream of things that happen the previous day.2 REM sleep is vital to the memory making process as shown by PET (positron emission tomography) scans of the brain. There is a great deal more brain activity during REM sleep after a period of intensive learning such as college students studying for finals (those who decide to sleep, that is).
Sleep apnea is also thought to have a negative effect on memory retention because of the frequent disturbances in the sleep that occur during apnea episodes. 1 The obstruction of oxygen actually destroys tissue associated with retaining memories in the structures called mammillary bodies. 3 Patients with Alzheimer’s disease also show shrunken mammillary bodies. During an episode, the blood vessels in the brain constrict killing cells and tissue.
In addition to the list of health benefits gained from sleeping, memory retention is also aided by adequate sleep. Through sleeping and getting help with sleep breathing disorders such as sleep apnea, you can insure that you are remembering and retaining information.
1. WebMD—Sleep Deprivation Effects on Memory; http://www.webmd.com/sleep-disorders/guide/sleep-deprivation-effects-on-memory
2. Maas, Dr. James B., Megan L. Wherry, David J Axelrod, Barbara R. Hogan, and Jennifer A. Blumin. Power Sleep: The Revolutionary Program That Prepares Your Mind for Peak Performance. New York : Villard, 1998.
3. University of California at Los Angeles Newsroom—Study links sleep apnea to memory loss; http://newsroom.ucla.edu/portal/ucla/ucla-study-links-sleep-apnea-to-51534.aspx